Field of the Invention
The present invention relates to a vehicle wheel axle assembly, particularly including aspects that facilitate the connection between axle of a vehicle wheel and the frame to which the vehicle wheel is mounted. More specifically, the present invention relates to a vehicle wheel axle assembly with a threaded connection to the frame that includes a rotational coupling feature to restrict inadvertent loosening of this threaded connection. The present invention is particularly applicable to a bicycle wheel axle assembly that facilitates the connection between axle of a bicycle wheel and the frame of a bicycle.
Discussion of Prior Art
Heretofore, the prior art threadable axle assemblies for bicycles and similar vehicles (commonly referred to as “through-axles”) are designed to work only with frames having “closed dropouts” with enclosed axial apertures to receive this through-axle. This arrangement requires that the through-axle be completely withdrawn from the frame in order to release the wheel from the dropouts. This renders this procedure as time consuming, complex, and clumsy, since the operator must now be able to manage three separate items: the bicycle, the wheel, and the through-axle.
Further, conventional through-axles rely on a generally fine pitch thread for this threadable assembly. This fine pitch arrangement provides good axial clamping to secure the axle assembly to the frame and also has a lower tendency to inadvertently unscrew or loosen. However, this fine pitch also requires many rotations of the through-axle to secure the axle assembly to the frame, which adds significant time the procedure of installing and removing the axle assembly (and wheel) from the frame. In contrast, a coarse pitch thread engagement has a steeper thread helix angle and thus considered a “faster thread” to axially advance the threaded engagement with fewer turns and greater speed than a fine-pitch thread. This rapid tightening/loosening of the through-axle saves precious seconds, particularly in race conditions.
Particularly in bicycle racing conditions, where seconds count, the added time and complexity of conventional through-axle is very problematic for the racer. This problem is significant enough that such through-axle systems have not been widely adopted in bicycle road-racing applications, where the ability to quickly swap out wheels (due to a flat tire, for instance) is particularly critical.
Further still, conventional through-axles commonly do not employ any locking features to restrict any inadvertent loosening or unthreading of this connection. Bicycles commonly experience a high degree of vibration, both on-road and off-road. This may induce the through-axle to loosen during the ride, which may permit the wheel to be wobbly in the frame, resulting in a wobbly connection and a reduction in control. Further loosening may cause the wheel to become inadvertently detached from the frame, a circumstance with potentially disastrous consequences.
Yet further, in the case where conventional slotted dropouts (“open dropouts”) are utilized, the through-axle is not captured and proper wheel retention relies solely on the axial clamping between the axle assembly and the dropouts. In such a configuration, an axle that is inadvertently loosened may more easily result in the wheel becoming detached from the frame. As such, it is that much more critical that the axle assembly does not loosen from the frame.